Japanese Unexamined Patent Application Publication (JP-A) No. 2002-164977 (paragraphs 0024-0032, 0040) (Document 1) describes an electronic device in which a driving portion (driving means) is attached to a display cover (plate-like member) disposed in front of a display for protecting the display, thereby vibrating the display cover to output a sound. Document 1 further describes that the driving means are disposed at a plurality of portions of the plate-like member, thereby enhancing the sound output.
Japanese Unexamined Patent Application Publication (JP-A) No. 2002-118894 (paragraphs 0019-0020, 0033, FIG. 14) (Document 2) describes a speaker in which linear vibrating devices are disposed at both side portions of a diaphragm and describes that, using a transparent glass, plastic, or the like as a material of the diaphragm, CRT, liquid-crystal, or other images behind the speaker can be viewed through the speaker. Further, Document 2 describes that a hybrid two-way driving system can be achieved by disposing another driving portion (piezoelectric vibrating device) in overlapping relationship to the linear vibrating device. Document 2 further describes that multiplexed audio signals of music, human voice, etc. are allocated to the respective driving portions to drive the diaphragm and that the driving signals are input with their frequency bands separated or not separated, thereby producing sounds so as to make the best use of the acoustic characteristics of the linear vibrating device and the piezoelectric vibrating device.